When a suspicious tissue mass is discovered in a patient's breast through examination, ultrasound, MRI, X-ray imaging or the like, it is often necessary to perform a biopsy procedure to remove one or more samples of that tissue in order to determine whether the mass contains cancerous cells. A biopsy may be performed using an open or percutaneous method.
An open biopsy is performed by making a large incision in the breast and removing either the entire mass, called an excisional biopsy, or a substantial portion of it, known as an incisional biopsy. An open biopsy is a surgical procedure that is usually done as an outpatient procedure in a hospital or a surgical center, involving both high cost and a high level of trauma to the patient. Open biopsy carries a relatively higher risk of infection and bleeding than does percutaneous biopsy, and the disfigurement that sometimes results from an open biopsy may make it difficult to read future mammograms. Further, the aesthetic considerations of the patient make open biopsy even less appealing due to the risk of disfigurement. Given that a high percentage of biopsies show that the suspicious tissue mass is not cancerous, the downsides of the open biopsy procedure render this method inappropriate in many cases.
Percutaneous biopsy, to the contrary, is much less invasive than open biopsy. Percutaneous biopsy may be performed using fine needle aspiration (FNA) or core needle biopsy. In FNA, a very thin needle is used to withdraw fluid and cells from the suspicious tissue mass. This method has an advantage in that it is very low-pain, so low-pain that local anesthetic is not always used because the application of it may be more painful than the FNA itself. However, a shortcoming of FNA is that only a small number of cells are obtained through the procedure, rendering it relatively less useful in analyzing the suspicious tissue and making an assessment of the progression of the cancer less simple if the sample is found to be malignant.
During a core needle biopsy, a small tissue sample is removed allowing for a pathological assessment of the tissue, including an assessment of the progression of any cancerous cells that are found. The following patent documents disclose various core biopsy devices and are incorporated herein by reference in their entirety: U.S. Pat. No. 6,273,862 issued Aug. 14, 2001; U.S. Pat. No. 6,231,522 issued May 15, 2001; U.S. Pat. No. 6,228,055 issued May 8, 2001; U.S. Pat. No. 6,120,462 issued Sep. 19, 2000; U.S. Pat. No. 6,086,544 issued Jul. 11, 2000; U.S. Pat. No. 6,077,230 issued Jun. 20, 2000; U.S. Pat. No. 6,017,316 issued Jan. 25, 2000; U.S. Pat. No. 6,007,497 issued Dec. 28, 1999; U.S. Pat. No. 5,980,469 issued Nov. 9, 1999; U.S. Pat. No. 5,964,716 issued Oct. 12, 1999; U.S. Pat. No. 5,928,164 issued Jul. 27, 1999; U.S. Pat. No. 5,775,333 issued Jul. 7, 1998; U.S. Pat. No. 5,769,086 issued Jun. 23, 1998; U.S. Pat. No. 5,649,547 issued Jul. 22, 1997; U.S. Pat. No. 5,526,822 issued Jun. 18, 1996; and US Patent Application 2003/0199753 published Oct. 23, 2003 to Hibner et al.
At present, a biopsy instrument marketed under the tradename MAMMOTOME is commercially available from ETHICON ENDO-SURGERY, INC. for use in obtaining breast biopsy samples. These devices generally retrieve multiple core biopsy samples from one insertion into breast tissue with vacuum assistance. In particular, a cutter tube is extended into a probe to cut tissue prolapsed into a side aperture under vacuum assistance and then the cutter tube is fully retracted between cuts to extract the sample.
With a long probe, the rate of sample taking is limited not only by the time required to rotate or reposition the probe but also by the time needed to translate the cutter. As an alternative to this “long stroke” biopsy device, a “short stroke” biopsy device is described in the following commonly assigned patent applications: U.S. patent application Ser. No. 10/676,944, “Biopsy Instrument with Internal Specimen Collection Mechanism” filed Sep. 30, 2003 in the name of Hibner et al.; and U.S. patent application Ser. No. 10/732,843, “Biopsy Device with Sample Tube” filed Dec. 10, 2003 in the name of Cicenas et al. The cutter is cycled across the side aperture, reducing the sample time. Several alternative specimen collection mechanisms are described that draw samples through the cutter tube, all of which allow for taking multiple samples without removing the probe from the breast.
Even given the many advantages of such multiple sample taking core biopsy devices, in certain applications some surgeons continue to use less expensive biopsy devices guided in real time by an ultrasonic system. These simple biopsy systems omit a full function control console that operates the cutter and vacuum assistance. Instead, a manually controlled hand piece advances a cutter by either stored spring force, a constant pneumatic pressure source, or motor power. Then the surgeon activates a cutter motor to effect the tissue sample. Thus, the surgeon is challenged to maintain the biopsy probe at a desired surgical site while manipulating the patient's breast.
Spring-fired core needle biopsy devices rely upon a firing mechanism that thrusts forward a needle and a cutter to penetrate the tissue and to obtain a tissue sample rather than prolapsing tissue into a side aperture of a probe. Frequently, a surgeon may encounter an area of dense tissue that is more difficult to penetrate than the surrounding tissue during core needle biopsy. In particular, the lesion or tissue mass being targeted in the biopsy procedure may be difficult to penetrate, requiring the physician to push the biopsy needle with considerable force and/or speed in an attempt to penetrate the lesion and collect a sample.
When encountering such an area of dense tissue, it is common for surgeons using the type of firing core needle biopsy device described above to fire the device in order to penetrate the lesion and obtain a sample. However, due to the length of the firing stroke of such devices, which may be as long as 0.75 inches, it is nearly impossible for the surgeon to control the travel of the needle after firing. Consequently, the long needle stroke may cause uncertainty as to the needle tip location post fire. This may cause the surgeon to obtain a sample from the wrong area. In addition to missing the targeted tissue, long firing strokes may cause the needle to puncture the chest wall or pierce the skin, particularly when the targeted area is near the patient's chest wall. Even if the skin is not pierced, the long travel of the needle, along with the likelihood that the needle will be pushed off course by the force of the firing stroke, may lead to needlessly increased trauma for the patient. These spring-fired biopsy devices also yield a single sample per insertion, thus limiting the amount of diagnostic and therapeutic treatment that may be achieved without the increased discomfort and tissue trauma from repeated insertions. Based on surgeons' use of the long firing stroke feature of current devices to aid in penetrating tissue lesions, it is clear that the medical community sees the benefit of firing assistance when inserting a probe to the desired location.
In commonly-owned and co-pending U.S. patent application Ser. No. 11/035,873, BIOPSY INSTRUMENT WITH IMPROVED NEEDLE PENETRATION to Beckman, et al., filed on Jan. 10, 2005, the disclosure of which is hereby incorporated by reference in its entirety, manual mechanisms are disclosed that impart small reciprocating motions to the probe of a core biopsy device to render assistance in penetrating tissue, yet cutting is performed after the probe is properly positioned, thus avoiding taking samples from the wrong location. Moreover, retraction of a cutter tube between severing samples allows for retrieval of multiple samples without having to reinsert the probe through the skin again. A control system that is tethered to a hand piece of this core biopsy system provides vacuum assistance and other motor control algorithms with numerous clinical and safety features incorporated. Generally, the core biopsy device portion of the system is disposable and the control system is reused.
While these multiple sample core biopsy instruments have numerous advantages, it is believed that the diagnostic and therapeutic opportunities of core biopsy procedures would be more widely used if an economical biopsy device without an elaborate control system existed which did not require the disposal of the entire core biopsy device.